Herein is disclosed, an intermediate transfer member, which, in belt form, can be seamed or seamless. The intermediate transfer member can be used in electrostatographic, such as xerographic, image on image, digital, and the like machines. In embodiments of a seamed belt, an image can be transferred at the seam of the belt with little or no print defects caused by the seam. In embodiments, xerographic component imageable seamed intermediate transfer belts comprising an electrically conductive filler dispersed in a binder are disclosed. In an embodiment, the binder is a polymer and the conductive filler is lignin sulfonic acid doped polyaniline. In embodiments, seaming of the belt can be formed by solvent or ultrasonic welding or by adhesive bonding. In embodiments, the problem of steep rise in conductivity with doping levels can be avoided or effectively be suppressed and process control is more robust. Also, in embodiments, glue and/or tape are not necessary to seam the belt, and the belt can be made by ultrasonic welding.
In a typical electrostatographic reproducing apparatus such as an electrophotographic imaging system using a photosensitive member, a light image of an original to be copied is recorded in the form of an electrostatic latent image upon a photosensitive member and the latent image is subsequently rendered visible by the application of a developer mixture. One type of development system used in such xerographic imaging machines is a dry developer comprising carrier beads, toner particles, charge control agents, and having lubricant particles mixed therein. Generally, the toner is made up of thermoplastic resin and a suitable colorant such as a dye or pigment. The developer material is brought into contact with the electrostatic latent image formed upon the photosensitive imaging member and the colored toner particles are deposited thereon in image configuration.
The developed toner image recorded on the imaging member is transferred to an image receiving substrate such as paper via an intermediate transfer member. The toner particles may first be transferred by heat and/or pressure to an intermediate transfer member, or more commonly, the toner image particles may be electrostatically transferred to the intermediate transfer member by means of an electrical potential between the imaging member and the intermediate transfer member. After the toner has been transferred to the intermediate transfer member, it is then transferred to the image receiving substrate, for example, by contacting the substrate with the toner image on the intermediate transfer member under heat and/or pressure, or alternatively by electrostatic attraction.
Transfer members enable high throughput at modest process speeds. In four-color photocopier or printer systems, the transfer member also improves registration of the final color toner image. In such systems, the four component colors of cyan, yellow, magenta and black may be synchronously developed onto one or more imaging members and transferred in registration onto a transfer member at a transfer station.
In electrostatographic printing and photocopy machines in which the toner image is transferred from the intermediate transfer member to the image receiving substrate, it is desired that the transfer of the toner particles from the intermediate transfer member to the image receiving substrate be substantially 100 percent. Less than complete transfer to the image receiving substrate results in image degradation and low resolution. Complete transfer is particularly desirable when the imaging process involves generating full color images since undesirable color deterioration in the final colors can occur when the color images are not completely transferred from the intermediate transfer member.
Thus, it is desirable that the intermediate transfer member surface has excellent release characteristics with respect to the toner particles. Conventional materials known in the art for use as transfer members often possess the strength, conformability and electrical conductivity necessary for use as transfer members, but can suffer from poor toner release characteristics, especially with respect to higher gloss image receiving substrates.
Polyimide substrate transfer members are suitable for high performance applications because of their outstanding mechanical strength and thermal stability, in addition to their good resistance to a wide range of chemicals. However, the high cost of manufacturing seamless polyimide belts has led to the introduction of a seamed belt. Polyimides with the best mechanical and chemical properties often exhibit poor adhesion at the seam even when commercially available primers are used. Further, polyimide materials exhibit relatively high surface energy and high friction, which decrease toner transfer efficiency in transfix and transfuse applications. In order to have high toner transfer efficiency, higher electric fields are typically required to transfer the toner and various costly cleaning apparatuses are employed to remove residual toner that does not transfer. In addition, substrates used for present imageable seamed intermediate transfer belt fabrication such as polyimides have high surface resistivity, which reduces the electrical latitude of the bonding adhesives used for seam joining and causes toner disturbance. Meanwhile, the seam rupture strength of these imageable seams can be relatively low due to superfinishing polish of the seam bonding area. These seams are fragile and may be easily damaged if mishandled.
Many of the above problems have been solved by the introduction of a polyimide belt having carbon black and polyaniline fillers dispersed therein. However, this belt, although preferred in terms of function, cannot be prepared by using the convenient ultrasonic seam welding process. The belt fabrication, therefore, employs a puzzle-cut joint. By itself, the puzzle-cut joint does not have strength to hold the belt together as the belt flexes and bends over the rollers of a belt support module during dynamic belt cycling under a normal machine service condition. It is therefore, required to use glue or adhesive, which is applied in the form of a tape either over or under the seam joint to permanently secure the puzzle-cut mating pairs and prevent the seam from disengaging during dynamic belt function in a machine. However, the application of a tape to permanently secure the puzzle-cut seam joint does add substantial thickness to the seam, which thereby has to undergo a time consuming and costly polishing process to reduce its thickness and provide a smooth finish.
Another serious problem of the extruded polyimide belt having polyaniline and carbon black fillers dispersed therein, is a very steep dependence of conductivity as a function of loading of polyaniline and carbon black. Belts, such as intermediate transfer belts, require a rather tight window of bulk resistivity. The result is difficulty with quality and manufacturing control, including dark-light petals on prints due to the inherent difficulty for providing excellent electrical property matching between the applied seam bonding adhesive and the bulk of the polyimide belt.
U.S. Pat. No. 5,549,193 relates to an endless flexible seamed belt comprising puzzle cut members, wherein at least one receptacle has a substantial depth in a portion of the belt material at the belt ends.
U.S. Pat. No. 5,721,032 discloses a puzzle cut seamed belt having a strength-enhancing strip.
U.S. Pat. No. 5,487,707 discloses a puzzle cut seamed belt having a bond between adjacent surfaces, wherein an ultraviolet cured adhesive is used to bond the adjacent surfaces.
U.S. Pat. No. 5,514,436 relates to a puzzle cut seamed belt having a mechanically invisible seam, which is substantially equivalent in performance to a seamless belt.
U.S. Pat. No. 5,525,446 describes an intermediate transfer member including a base layer and top thermoplastic film forming polymer layer. The base layer can include a polycarbonate film, and the top layer can include polybutylenes. The belt can comprise an adhesive layer such as a polyvinylbutyral adhesive layer.
It is desired to provide an intermediate transfer member wherein, in belt form, the belt can be formed by solvent welding or ultrasonic welding. It is further desired to provide a seamed belt wherein glue and/or tape are not required to seam the belt. It is also desired to provide an intermediate transfer member in which the problem of steep rise in conductivity with doping levels can be suppressed or eliminated.